This invention relates to a potable water filter which can be used for domestic use. Water filters of this type may include a housing having an inlet and an outlet which are connected, respectively, to a source of water and a drinking water outlet. The water filter includes a carbon filter element or the like through which the water flowing to the drinking water outlet passes. A particle filter element may also be provided to filter the water flowing to the carbon filter element.
One problem with water filters of this type is that the particle filter element tends to become dirty or clogged with undissolved solids before the end of the useful life of the carbon filter element. Consequently, the useful life of the water filter is reduced. Although it is known to attack this problem by backflushing of the filter elements, this has the disadvantage of requiring a reversal of water flow through the filter. In addition, undesirable contaminant build-up can occur during the interval between backflushes. It is also known to flush the dissolved solids from a reverse osmosis water filter. However, this does not prolong the useful life of the particle filter which is located upstream from the reverse osmosis membrane.
To provide for at least a minimum residence time of the water in the carbon filter element, a flow regulator can be utilized. The flow regulator provides for an essentially constant flow rate through the filter when the drinking water valve is fully open, essentially independently of water pressure variations at the inlet or pressure drop across the filter elements. Although this is a desirable concept, prior art water filters have generally employed flow regulators which are relatively expensive and complex.